Across
- 2. This gas helps clean swimming pools
- 3. Often used to make rings and jewellery
- 5. The element's chemical symbol is Ar
- 7. The simple particle in the particle model
- 9. You can find all the elements listed here
- 10. About 78% of the Earth's atmosphere
- 11. This gas can be used to fill party balloons
- 12. This element is mostly known to build maintain strong bones
- 13. This element's chemical symbol is Be
Down
- 1. This element's chemical symbol is K
- 4. About 21% of the Earth's atmosphere
- 6. This element is black and usually can be found inside a pencil
- 8. The element''s chemical symbol is Mg
- 11. This element's number is 1